The Supreme Court seems open to a Texas law aimed at blocking kids from seeing online pornography. But the justices could still send it back to a lower court for more consideration of how the age verification measure affects adults’ free-speech rights.

The oral arguments lasted two hours with opposing sides making their case on whether the Texas law infringes on the free speech rights of adults.

The law, meant to shield minors from sexual materials on the internet by requiring adults to prove they are 18, was challenged on First Amendment grounds.